<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style>
    
  </style>
</head>
<body>
  
</body>
<script>
  
  console.log( "hello" );
  console.log( typeof "hello" );
  console.log( "123" );
  console.log( typeof "123" );
  console.log( "null" );
  console.log( typeof "null" );
  console.log( "true" );
  console.log( typeof "true" );
  console.log( "{}" );
  console.log( typeof "{}" );
  console.log( "[]" );
  console.log( typeof "[]" );
  console.log( "function(){}" );
  console.log( typeof "function(){}" );
  console.log( "'" );
  console.log( typeof "'" );
  console.log( '"' );
  console.log( typeof '"' );
  console.log( ' ' );
  console.log( typeof ' ' );
  console.log( "" );
  console.log( typeof "" );



  console.log( 123 )
  console.log( typeof 123 )
  console.log( typeof 123.456 )
  console.log( typeof -123.456 )
  console.log( 0 )
  console.log( typeof 0 )
  console.log( NaN )
  console.log( typeof NaN )


  console.log( true )
  console.log( typeof true )

  console.log( undefined )
  console.log( typeof undefined )

  console.log( {} )
  console.log( typeof {} )

  console.log( [] )
  console.log( typeof [] )

  console.log( function(){} )
  console.log( typeof function(){} )

  console.log( null )
  console.log( typeof null )

  // 计算机存储的数据都是二进制：0和1

  console.log( "-------" )

  console.log( typeof typeof {} );
  console.log( typeof typeof function(){} );
  console.log( typeof typeof undefined );
  console.log( typeof typeof 123 );
  console.log( typeof typeof null );
  console.log( typeof typeof [] );



</script>
</html>